Miyong T. Kim , RN, PhD, FAANTam Nguyen, RN, PhD
School of NursingThe Johns Hopkins University
Baltimore, MD
Funding sourcesNational Heart Lung Blood Institute( NHLBI R01HL085567)Institute for Diabetes, Digestive disease and Kidney (R18 DK08936)National Institutes of Nursing Research (NR010992)
Conflict of Interest• None
ObjectivesBriefly review the major HL measurement issue related with intervention research and practice Discuss the process of developing and validating disease specific health literacy measurement tool using real study examples
Adequate Health Care
IndividualLanguageTransportationFear or being intimidated by main health care system
PsychologicalFeeling of marginalizationLoss of self‐confidenceRole conflict /dependency on others“Do not want to be a burden to family”Depression
Environmental/financialSafetyCost of medicationAccess to health care
Sources: Lee HB, et al. Psychiatry Investig. 2008;5:14‐20.Kang JH, et al. Ethn Dis. 2006;16(1):145‐51.
Extent of Limited Health Literacy by Race/Ethnicity
Ethnic minorities have a higher percentage of below basic health literacy than Whites
Hispanics, American Indians/Alaskan Natives and Blacks most affected
Source: NAAL, 2003
Health Literacy in ESL
Adults who learn English at a later age, have lower literacy scores than those who learn English at an earlier
age
Source: NAAL, 2003
Adequate Health Care
IndividualLanguageTransportationFear or being intimidated by main health care system
PsychologicalFeeling of marginalizationLoss of self‐confidenceRole conflict /dependency on others“Do not want to be a burden to family”Depression
Environmental/financialSafetyCost of medicationAccess to health care
Sources: Lee HB, et al. Psychiatry Investig. 2008;5:14‐20.Kang JH, et al. Ethn Dis. 2006;16(1):145‐51.
Intervention Strategies
Health literacy Structured psycho- behavioral DM education delivered
Home glucose monitoring with a telephone transmission system (HGMT)
Health literacy focused Telephone counseling with a bilingual nurse case manager6 weeks6 weeks
24 weeks24 weeks
Culturally tailored comprehensiv e behavioral intervention
Culturally tailored comprehensiv e behavioral intervention
24 weeks24 weeks
Kim MT et al., (2009). Diabetes Educator, 35(6), 986‐994
Intervention Strategies
Health literacy Structured psycho- behavioral HBP education delivered
Home HBPwith a telephone transmission system (HGMT)
Health literacy focused Telephone counseling with a bilingual nurse case manager6 weeks6 weeks
24 weeks24 weeks
Culturally tailored comprehensiv e behavioral intervention
Culturally tailored comprehensiv e behavioral intervention
24 weeks24 weeks
Kim MT et al. (2011)
Journal of Clinical Hypertension, 13, 605–612. PMID:21806771
Intervention Materials for Health LiteracyHealth literacy word slides
Intervention Materials for Health LiteracyEnglish Dialogue slides
Major barriers to implement HL focused intervention
Limitation on outcome measurement
* Sensitivity to capture the intervention effect* Global measure vs. disease specific instrument
Researcher skepticism :
“Can Health Literacy be improved by a short‐term intervention?”
Major methodological contributors of false “ non-significant “ findings in intervention research
Randomization method may not yield comparable treatment & control groups in terms of attributes.The treatment (independent variable) may not be powerful enough to produce a change. Measurement of the independent variables may not be sufficiently specific or sensitive to detect change.The timing (interval) of the test and measurements of data may not allow for detection of effect of the independent variable. Uncontrolled extraneous variables have a dominant effect on the dependent variables or independent variable.
High Blood Pressure Health Literacy Scale (HBP‐HLS) Kim et al, 2011
43‐Item HBP‐HLS30 print items13‐functional items
Development & validation of scale was guided by several principles:
The use of simple word recognition test would be appropriateThe addition of functional items would ensure the assessment of comprehension Making it content specific to HBP will reduce the shame and stigma of limited HL, and make it more relevant for targeted clinical interventionsInclusion of community member input was necessary
Wanted to further support its utility in other ethnic populations such as Vietnamese American
Create a shorten scale that was more applicable in clinical settings
Kim MT,
Nguyen T, et al, (2011). Development and Validation of the High Blood Pressure Focused Health Literacy Scale.
Patient Education & Counseling. PMID:22030252
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Develop Health Literacy Tool
Pilot and Refine Tool
Exploratory Factor Analysis
Reliability & Validity
Item Response Theory Analysis
Exploratory Factor Analysis
Reliability &Validity
Assess relationships with HBP‐HLS
Korean American Vietnamese American
Aim 1
Aim 2
State of Science of HL Measures
59 existing instruments; 29 general, 30 content/context‐specific
None of the disease specific measures were related to HBPEvidence supporting use of disease specific HL measures was not clear, but strong arguments were made regarding their usefulness in reducing the shame and stigma of limited HL. Most were validated with White (n=33), Black (n=29), and/or Hispanic (n=14) Americans samples
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General statistical theory that uses logistic models to describe the relationship between an individual’s ability and how they respond to an item
This relationship is described by the item characteristic curve(ICC)
Interpreted by itsDifficultly parameter, bDiscrimination parameter, a
Information function curves
0
0.1
0.2
0.30.4
0.5
0.6
0.7
0.8
0.9
1
‐3 ‐2 ‐1 0 1 2 3
Probability of Response
Heallth Literacy Ability (T )
2 parameter logistic
model
0
1
2
3
4
5
6
7
8
9
‐3 ‐2 ‐1 0 1 2 3
Information
HBP Health Literacy (T )
b
a
IRT Process
Test for Differential Item Functioning (DIF)
Development sample(n=323)
Validation sample(n=317)
Assess model fit
Calibrate items using best model
MLE
EFANested ModelsS‐X2
LD X2
MLEIRTPRO®
Items TrimmingICCInformation Functions
Preliminary validity assessment
Correlate &ReassessRelationships
Characteristics Korean American (n=440)
Vietnamese American (n=200)
n(%) or mean±SD n(%) or mean±SD Age 70.9±5.5 57.0±14.6 18-29 12 (6.0%) 30-44 22 (11.0%) 45-59 72 (36.0%) 60-69 186(42.3%) 56 (28.0%) 70-79 223(50.7%) 29 (14.5%) ≥80 31(7.0%) 9 (4.5%) Gender Male 134(30.5%) 97 (48.5%) Female 306(69.5%) 103 (51.5%) Education ≤ Middle school 165 (37.5%) 71 (35.5%) High school 126 (28.6%) 55 (27.5%) ≥Some College 149 (33.9%) 74 (37.0%) Year in U.S. Observed HBP-HL Score 0-10 11-20 21-30 31-43
24.2±11.3
202 (46%) 47 (11%) 61 (14%)
130 (30%)
19.0±11.5
31 (16%) 10 (5%)
25 (13%) 134 (67%)
Results:
Differential Item Functioning (DIF)
00.10.20.30.40.50.60.70.80.91
‐3 ‐2 ‐1 0 1 2 3
Probability of Corerct Response
Health Literacy Ability (T )
Circulation (KA) Circulation (VA)
00.10.20.30.40.50.60.70.80.91
‐3 ‐2 ‐1 0 1 2 3
Probability of Corerct Response
Health Literacy Ability (T )
Normal PB (KA) Normal BP (VA)
35‐items, (‐) DIF 8‐items, (+) DIF
Results:
Item Trimming (Interval 1)21
ICC Information Functions
Results:
ICCs of 43 versus 10‐item HBP‐HLS
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0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
‐3 ‐2 ‐1 0 1 2 3
Probability of Correct Response
Health Literary Ability (?)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
‐3 ‐2 ‐1 0 1 2 3
Probability of Correct Response
Health Literary Ability (?)
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ConclusionsThe HBP‐HLS was effectively shorten by over 75% to 10‐item (7 print, 3 functional) while retaining optimal precision, content coverage and preliminary evidence of validity
Measurement equivalence was achieved in two ethnic groups whose native language is vastly different
This has tremendous implications for participant burden, feasibility of use in clinical settings, and cost
survey
Future HL instrumentation Research direction
Contribute to NIH Patient Reported Outcome Measurement Information System (PROMIS) health literacy item bank
Implication on Health Disparity Research
Given the growing health disparity gap in chronic disease management among those special populations, researchers and clinicians should consider an educational intervention that directly influences health literacy as a viable option to address this important issue.